It's hard to pick just 15. And hard to choose which won't be included, like the Journeyman Project games, Toonstruck, Timelapse, Amerzone, Discworld, Ripper, Tex Murphy, etc. are also so good. (I'm not sure how well Tex Murphy, Ripper, and Toonstruck work on XP though, or this list might look a little different).

I'm assuming all of these will work on a modern XP computer, either with an emulator or au naturel.In alphabetical order -